Kyosoku Eisho, also known as the Atomic Hero: Biohazardous and by his childhood nickname Gojira, is a student in Class 1-A at U.A. High School, training to become a Pro Hero. He is the son of two Pro Heroes Radiation Hero: Radioactivo and Toxic Hero: Virulenta and the grandson of the former Pro Hero Venom Hero: Viperae.


Kyosoku is a rather muscular young man with a very lizard-like appearance. His face, arms, and legs have bumpy black scales in the mix of his tan skin. His brown hair has shaved into an undercut. The ends of it has green highlights. He has forest green eyes that are slightly slanted to the middle. He also has a black tail that is also lizard-like, with small spikes on it. It gives off a slight glow when he is about to shoot his Atomic Breath Quirk.

Kyosoku wears the usual male school uniform, but instead of the school shoes, we wears large green boots with white lace ups.

His Hero costume consists of a black suit with blue triangle patterns that resemble the toxic warning sign. He has metal shoulder and knee pads and has scale-patterned gauntlets on his forearms and forelegs, which resembles the original Godzilla scale pattern. His belt contains small pouches which carries batteries and radiation cups. He was barefoot when he showed his hero construe in Season 1.

In the Provisional License Exam Arc, Kyosoku updated his costume, with his feet having metal claws that resemble Godzilla’s feet. He also has tubes sticking from the gauntlets to the pockets to use on his Super Move: Atomic Fists and Super Move: Ground Zero Thump. He also wears a wired guard similar to Eijiro Kirishima’s and blue visors.

After he upgraded his Quirk in the Shie Hassaikai Arc after the raid, he put a metal clamp on the end of his tail that opens and closes when he doesn’t use his power through the tail.

His winter costume was only a winter jacket with the same label with a high collar.



Kyosoku is shown to be quiet and a threatening individual when Izuku first met him with eyes that show “great hatred and rancor”, though this was only due to his harsh training treatment and his resentfulness towards his mother. Though he didn’t get along much with Izuku, Tenya, and Ochaco, he did acknowledge their presence and is shown to thank them for their friendship.

Under the hatred and blank expressions, Kyosoku is shown to have a soft spot for his siblings and his other friends from Shiketsu High, despite them being U.A.’s rivals, and despite not wanting new friends from U.A., he was viewed as a great friend to Izuku, Tenya, Ochaco, Tsuyu, Denki, and mostly Eijiro Kirishima and Katsuki Bakugo.

In battle, he is shown to be cautious and stops before he can react to situations, and doesn’t like to rush, especially in tough situations. He is shown to have a determined and aggressive side due to his treatment in his childhood, and he does this to “let his emotions go”, as shown when he fought against Lomuna Shimizu. Kyosoku will let his emotions get the best of him, which gets him to his 40% limit of his Quirk.

Other than that, he cares for the well-being of others and won’t hesitate to attack those who provoke him or the people he cares for. He will show deep respect for those who see him as an equal and won’t for those who see him as someone with the most powerful Quirk.


Overall Abilities: Kyosoku is shown to be very strong in both combat and on emotional occasions. He has stated that he was trained by his mother when he developed his Quirk and was already a muscular man by the time he was in middle school at the third year. Despite having a Quirk, he sometimes doesn’t use it and uses his combat abilities against the opponent and actually has begin to become more stronger when attending U.A.

During the Sports Festival Arc, he was shown practicing his aim to a target and was proven useful during his battle tournament against Lomuna, Aikan Hofuku, and Katsuki, though he lost to the latter after accidentally using 40% of his red-orange power against Katsuki’s Stun Grenade. Afterwards, he trained under his mother again during weekends and after school to increase his limit more.

During the Forest Training Camp, Kyosoku was practicing using his new red-orange power while also engaging in combat on a mountain, trying to decrease his sore neck pain and increasing his ranged combat, which he barely relied on when he first entered U.A. High. Thanks to his training, he finally was able to resist through his drawbacks and therefore use his red-orange Quirk power and also use his new moves.

While working on his Super Moves, he developed one he called Atomic Fists, while also creating minor ones to use during battle with his newfound combat skills, now increasing more of his Quirk and giving him more use of his physical strength and abilities. With this use, he was able to pass the Provisional License Exam and get his license.

During the Shie Hassaikai Raid Arc, he was able to produce green energy, which surpasses his original limit of 40% Red-Orange, which came from his body after seeing his half-sister Mere severely injured and his father Ketsubeki nearly dead. After the raid ended and Eri was saved, Kyosoku decided to get his father to train him so he can contain control of his new limit.

In My Hero Academia: Heroes: Rising, Kyosoku has improved his Quirk and combat skills and engages in battle, creating his new move Toxic Heat Wave while attacking Nine along with Izuku and Katsuki. After using most of his power, with no use, Kyosoku stored up his radiation and electricity and shot out his new limit Purple Laser aka Violet Disaster. Along with Katsuki, he created the Super Move: Doubke Death Disaster, and while using his purple power, he finally shot it to Nine and defeated him. He went unconscious afterwards, which meant he hasn’t gotten control of it yet.


Atomic Breath ( 原子ブレス Genshi buresu): A mix of his father!s Radiation Feeder Quirk and his mother’s Toxic Waste Quirk, Kyosoku’s Quirk allows him to shoot a blue atomic heat beam from his mouth, which is much more powerful than fire. Because of this, he has maple leaf-shaped dorsal fins on his back and a second brain under them all. It is so powerful that it can pierce through a building within 2-3 meters away. In order to power it up, Kyosoku has to feed himself with radiation or electricity to make it stronger. Using the beam too much can cause a sore throat, and feeding on too much radiation or electricity can make the beam more stronger and harder to control, going at it’s maximum temperature and it’s change of color, which can be classified by how strong it is.

As part of his training Kyosoku fires his new limited red orange breath at a rock on a mountain 2x his limit, decreasing his sore throat and neck pain. Because of this, it may be possible he will be able to fire it with his other level of powers.

Blue: The normal color of his Atomic Breath, which according to him took some time to adjust to when he first manifested it. Can be powered with only 10-20% of radiation, and below that is weaker than fire itself. He called it “Blue Dragonoid Fire”.

Red-Orange: This was the next stage of his Atomic Breath, which he unfortunately activated when he was battling Lomuna Shimizu in the Sports Festival. It shot out a red-orange color, which was more powerful than his Blue Dragonoid Fire stage. It can burn through metal and ice (as demonstrated with Lomuna, who’s Quirk allowed her to produce ice, and the way he shot through a metal pipe in his fight against Wolfram). Can only be fired with 30-40% of radiation stored in his second brain. Kyosoku calls it “Red Phoenix”.

Green: This was the third stage after his Red Phoenix stage, in which he first shows during his fight against a Yakuza member in the Shie Hassaikai raid. With this, he can produce a green fire that can burn through nearly anything (except for the earth itself). It requires 50-60% of radiation to activate this stage. He calls it “Green Danger”.

Purple Laser: After “Green Danger”, this gives Kyosoku to shoot purple lasers instead of the usual fire figure he shoots from his mouth and tail. This was first used against Mummy during his hero work at Nobu Island, exceeding from his limit of 60%. This stage can be powered up with 70-90% of his Quirk, giving him an advantage to shoot lasers from his dorsal fins as well. He calls this stage “Purple Disaster”.

Magenta/Dark Energy: When Kyosoku rushes to Katsuki’s and Izuku’s aid, he suddenly uses his fifth and final stage of his Quirk, which gave him up to 100% of his full power. With all the training he had from his Quirk, he finally excels to his final stage. This gives him a magenta and dark tone-like energy that seemingly glows like stardust in the red sun. Though he can finally use his full power, it unfortunately destroyed his second brain, which was the source of the radiation he feed on. However, he can regrow the brain over time, and by the time it was the Joint Training Arc, his brain finally grew back into its original state. He called this power “Alpha Deity Power”.

Super Moves:

Atomic Fists ( 原子拳 Genshi ken): This is a move for when Kyosoku blasts his gloves with his atomic breath, which gives him advanced power to his hands. When punched with it, it feels like being punched by a ray of fire. If used with either the green or red/orange beam, this can give off a more powerful and destructible blow.

  • 80 Degrees: Hazardous Blow: Kyosoku delivers an uppercut with his Atomic Fists move.
  • 100 Degrees: Radioactive Claw: Kyosoku grabs the face of the opponent with his Atomic Fists move and with full force, smashes the opponent on the ground.

Ground Zero Thump: Inspired by his half-sister’s Super Move: Thunder Thump, Kyosoku increases the radiation in his legs and with a large jump, he can make the earth crack below him and drive away his opponents with one jump. First used against Gang Orca’s Sidekicks during the Provisional Hero License Exam.

Toxic Heat Wave: By increasing his radiation on his breath, he can fire his red-orange Atomic Breath and let it get all over his body to fire it towards the opponent using 120 Degrees of the power to deliver a massive amount of heated power. This has required lots of training from his Internships and was later proven useful with his Green Danger power during the Shie Hassaikai Raid. First used in his battle against Lomuna in the U.A. Sports Festival.

Death’s Kiss: This Move allows Kyosoku to shoot his Atomic Breath into someone’s mouth and into the throat, killing them in the process. This move was first used in the new movie My Hero Academia: Country Heroes (not real) against Dracova.

Thermalnuclear Pulse: This Move allows Kyosoku to release his firey stage that he stores in his body, which causes things to melt around him. With enough training from his Hero-Work Study under his own father, he can use it on the other stages of his Quirk.


5/5 A
4/5 B
4/5 B
4/5 B
3/5 C
Kyosoku's stats, according to the creator.
5/6 A
3/6 C
4/6 B
4/6 B
Godzillian Features
6/6 S
Kyosoku's stats, according to the Ultra Analysis Book


Gojira’s Teeth: The wired guard Kyosoku uses around his mouth stays still when using his Quirk, which is shown to be helpful as he can’t control his Atomic Breath and will spread his mouth open, creating sore jaw pain.

Goji-Visors: Kyosoku wears blue visors to protect his eyes from the light produced by his Atomic Breath.

Fireproof Clothing: The costume was designed to resist the mutated fire Quirk Kyosoku shoots out from his body, though it had to be fixed multiple times to get the material right.

Goji-Gauntlets: The navy blue scale-patterned gauntlets carry some of the radiation used for his Super Move: Atomic Fists and are shown to be resistant to the mutated fire inside him. They have tubes that stick to his pouches on his belt, which carries the radiation cups and batteries. They are also two other ones on his forelegs, which has the same use as the gauntlets.

Goji-Claws: This equipment is made of some heavy metal that lets Kyosoku stay in place whenever he uses his Quirk, but is light enough for him to run in. It is also cushioned on the inside so his feet can be comfortable, unlike when he went barefoot before using this new equipment.

Tail’s Mouth: This is made of metal resistant to the Atomic Breath and is clamped on the end of Kyosoku’s tail for when he uses his Quirk with it. When it is closed, it usually means it stops the tail from shooting any further or it is necessary. It is a suggested item and was made by Mei Hatsume for his upgraded Quirk.

Metal Knee and Shoulder Pads: Used to prevent injury.


  • Kyosoku was originally gonna be a reptile Quirk user whose sister was a villain who has a son. That son became his quadruple brother Kaitan and the villain sister became his quadruple sister Hichu who all attend U.A. in different classes. Kyosoku was also originally gonna have a long-dead brother, but that became his other quadruple brother Tenka.
  • Kyosoku was also gonna be a dragon Quirk user, but that was scratched off.
  • According to his Profile
  1. His favorite food is yakitori
  2. His favorite thing is Godzilla, aesthetics, and natural phenomenon.
  3. Kyosoku’s favorite Pro Hero is the American Monster Hero: Godzillo, which explains some of his posters of him in his dorm room and how he was extremely happy when he personally saw him while he was touring with Izuku Midoriya and Melissa Shield.
  • Kyosoku, Katsuki Bakugo, and Ochaco Uraraka share the same costume designer.
  • His lizard-like appearance and fire-like Quirk is similar to Godzilla, hence his childhood nickname and admiration for the franchise.
  • Most of his Super Moves were named after canon Godzilla franchise abilities Godzilla possesses himself. For example, Thermonuclear Pulse was the same ability Godzilla used in Godzilla:King of The Monsters during his final battle with King Ghidorah.
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